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One-third of Americans admit that they financially cheat on a partner

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Have you ever done something with your money that your partner or spouse wouldn't approve of, and kept it a secret?

If so, you're not alone.

More than 30% of Americans admit they have committed some form of financial infidelity, according to a online survey of more than 2,000 adults conducted for CreditCards.Com.

"A lot of times, what this goes back to is communication or a lack thereof," said Ted Rossman, a senior industry analyst for CreditCard.com. "It can really undermine trust if you're keeping secrets."

In fact, more than half of adults surveyed said that financial cheating is just as bad or worse than physical cheating.

"It's hard enough to meet your financial goals when you're working together," Rossman said. "If one person is siphoning off money or doing their own thing, it just makes it that much harder."

Why partners have money secrets

There are a number of reasons why adults are dishonest about their finances with their partners, the survey found.

The most common culprit? About one third never felt the need to share their finances.

"For some, honestly I don't think they recognize it as financial infidelity," said Nathan Astle, a certified financial therapist and founder of Relational Money in Manhattan, Kansas.

"It all depends on the relationship and what the rules are that the couple set out and unfortunately, because money is so taboo, most couples don't really know how to talk about it very well and they aren't intentional about those rules," he added.

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Another 30% said they have a desire to control their own finances or maintain privacy around money, and 25% said they were embarrassed about the way they handle money.

There were fewer adults who had different reasons for keeping a financial secret – 14% said they didn't trust their partner with money, and another 14% had a secret stash in case the relationship ended poorly. For 13%, the extra money was being used to support an addiction.

How to navigate financial infidelity

When Astle works with couples experiencing financial infidelity, he first addresses the emotions that come up for each person and works to help them regulate their feelings.

For many people, hiding money or debt may be due to shame around finances or because they have gone through a bad breakup or divorce and feel safer having a savings account of their own, he said. Those emotions need to be addressed to move forward.

"Money is always emotional, you can't separate it," said Astle, adding that doing this helps couples come to a place where they can have productive discussions around money. "Once we have the emotions down, we can make a plan and follow through on that."

Astle also noted that financial infidelity is different from financial abuse, which is generally when money is being used to manipulate or control someone in a relationship.

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How couples should split their finances

Yours, mine and ours

Most adults in committed relationships – either married, in a civil partnership or living together – keep some of their finances separate.

More than half of couples keep at least some separate financial accounts while 34% mix joint and separate accounts. Only 23% keep everything completely separated, according to the survey.

Younger couples and those from lower-income households making less than $50,000 annually are more likely to keep some or all their money in individual accounts as opposed to having joint ones. Middle-income households are more likely to pool all assets, and the highest earners often opt for a blended approach of some combined, some individual accounts.

"It's totally fine to have separate accounts if you agree on it," Rossman said. "The semantics are up to you."

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Astle said that solutions are generally what ends up being best for the couple, but he usually suggests a "yours, mine and ours" approach.

The details can work out differently for each couple and situation, but what is important is that everyone is on the same page about what money is coming in, what's going to shared expenses, and what is allocated to individual spending.

Once a plan is established, regular check-ins and communication are still necessary, he said.

"A lot of trouble can be avoided if couples are open and honest about their financial situation and they're regularly talking," Astle said.

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